1. Field of the Invention
This invention relates to disk drive suspensions having actuation and microactuation capabilities, and more particularly to suspensions in which the microactuation is effected by a microactuator acting on relatively movable portions of the suspension mount plate. In one embodiment, the suspension mount plate defines a pocket for the microactuator such that dimensional changes in the microactuator relatively shift connected portions of the mount plate to effect microactuated translation of the suspension load beam and flexure.
2. Description of the Related Art
Disk drive suspensions typically include a mount plate that is fixed to an actuator e.g. by staking, and the mount plate is attached to a load beam. The movement of the load beam by the actuator positions the slider carried by the load beam relative to a disk track. For more finely adjusted positioning a microactuator is used, typically a dimensionally variable body responsive to an applied voltage such as a piezoelectric crystal (PZT). These bodies typically provide length-wise or breadth-wise actuation and are generally coupled to the load beam and use hinges to amplify the stroke generated by the microactuator that have been physically separated from the microactuator body. The known relative locations of the load beam, hinge and microactuator body have been problematic. In previous designs, single PZT micro-actuator piezo bodies were not centrally placed with respect to the longitudinal axis of the suspension. The piezo bodies were actuating not in plane with the mount plate of the suspension, and stiffeners (shock absorbers) that minimize the loading effect on piezo ceramics and improve modal frequencies, were necessarily physically separated from the actuator body. Physical separations, however, among the actuator body, hinge and stiffener parts form discontinuities (voids) in the suspension adjacent the mount plate that degrade the dynamic performance, i.e. lower modal frequencies, and adversely affect the shock absorption capabilities of the suspension. Further, asymmetry of mass about the longitudinal axis can cause out-of-plane vibration modes to flare up, as will similarly having the actuation plane not in plane with the mount plate. Stiffeners, provided to improve the shock and dynamic performance of the head gimbal assembly HGA, can, when typically placed distally of the PZT mechanically block the PZT, thus attenuating the mechanical amplification (leverage) inherent in the structure, limiting the attainable stroke levels of the system.